Spatially resolved imaging of opto-electrical property variations

ABSTRACT

Systems and methods for opto electric properties are provided. A light source illuminates a sample. A reference detector senses light from the light source. A sample detector receives light from the sample. A positioning fixture allows for relative positioning of the sample or the light source with respect to each other. An electrical signal device measures the electrical properties of the sample. The reference detector, sample detector and electrical signal device provide information that may be processed to determine opto-electric properties of the same.

STATEMENT OF GOVERNMENT INTEREST

The United States Government has rights in the invention describedherein pursuant to Contract No. DE-AC02-06CH11357 between the UnitedStates Department of Energy and UChicago Argonne, LLC, as operator ofArgonne National Laboratory.

FIELD OF THE INVENTION

The present invention generally relates to characterization of solarcells and other optoelectronic devices such as photodetectors, CCD,light sensors, etc.

BACKGROUND OF THE INVENTION

A solar cell is a device that converts light into electrical energy.Measurements of opto-electrical properties are of a paramounttechnological importance. One example of opto-electrical properties isquantum efficiency of solar cells. A solar cell can be described as anactive layer (the layer where conversion of light into electricityhappens) sandwiched between two current collectors (electrodes). Quantumefficiency (QE) is a measure of solar cell performance, which is thepercentage of photons hitting the photoactive surface that producecollected charge carriers. From a basic science point of view, QEmapping provides information about band structure of the absorber insidethe solar cell, as well as a direct measure of performance improvementsdue to nanostructuring and light management strategies. From an appliedpoint of view, QE mapping is a useful tool for quality control andfailure analysis. It is usually measured by shining monochromatic lightonto a photovoltaic cell and recording electrical output of the device.QE mapping is also useful for understanding performance degradation ofsolar cells, a ubiquitous problem in the solar cell industry. There areseveral mechanisms for performance degradation with degradation of theactive layer and contacts being the most prevalent.

There is an unmet need for a system for efficient quality control andfailure analysis for solar cells and other optoelectronic devices.

SUMMARY OF THE INVENTION

One embodiment of the invention relates to a system for measuring theopto-electrical properties of a sample. The system comprises a lightsource and a reference light detector in direct communication with thelight source measuring light intensity output of the light source as afunction of light wavelength. An optical fixture is in opticalcommunication with the light source. A positioning fixture is configuredto provide three-dimensional positioning of the sample relative to thefocal point of the light beam. A sample light detector is in opticalcommunication with the sample to receive light from the sample. Thesystem further includes an electric signal device for the measurement ofelectrical properties of the sample.

In one embodiment, a method for data acquisition of spatially resolvedopto-electrical signal is provided. The sample is positioned relative toa light source to define a first portion of the sample. A first lightbeam is emitted from the light source. Intensity of the light output ofthe light source is measured within a specified bandwidth. The firstsampling beam interacts with the first portion of the sample. Theinteracted light is detected with a sample light detector. A secondlight beam is emitted from the light source. Intensity of the lightoutput of the light source is measured within the specified bandwidth.The second sampling beam interacts with the first portion of the sample.The reflected second sampling beam is detected with a second lightdetector.

In one embodiment, a computer-implemented machine for collectingspatially resolved signals of opto-electrical properties of a sample isprovided. The computer implemented machine comprises a processor; and atangible computer-readable medium operatively connected to the processorand including computer code. The tangible computer-readable mediumincludes computer code configured to: position the sample with apositioning fixture to define a first portion of the sample; emit alight beam from a light source; measure intensity of the light output ofthe light source within specified bandwidth; 3) detect the referencebeam with a reference detector; 4) reflect the sampling beam on thefirst portion of the sample; 5) detect the reflected sampling beam witha sample detector; 6) collect time-stamped intensity of the light outputof the light source within specified bandwidth; 7) collect time-stampedelectrical response of the sample; 8) collect time-stamped intensity ofthe reflected sampling beam; 9) record position of the sample; andreposition the relative position of either the sample or light source tothe other to define another portion of the sample for whichopto-electrical properties have not been calculated and repeat steps1-9.

Additional features, advantages, and embodiments of the presentdisclosure may be set forth from consideration of the following detaileddescription, drawings, and claims. Moreover, it is to be understood thatboth the foregoing summary of the present disclosure and the followingdetailed description are exemplary and intended to provide furtherexplanation without further limiting the scope of the present disclosureclaimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, aspects, features, and advantages ofthe disclosure will become more apparent and better understood byreferring to the following description taken in conjunction with theaccompanying drawings, in which:

FIG. 1 is an illustration of one embodiment of a system for mappingopto-electrical properties.

FIG. 2 is a schematic diagram of one embodiment of a system for mappingopto-electrical properties.

FIGS. 3A-D illustrate spatially resolved QE maps (oversaturated linesare the top current collectors in A-D): A) light wavelength 1100 nm(spatial variations of QE ˜50-100 μm are visible); B) light wavelength1100 nm (current collector square grid is visible); C) light wavelength1000 nm; D) light wavelength 800 nm (spatial variations of QE ˜50-100 μMare visible); FIGS. 3E and F illustrate QE maps from a prior commercialmachine: E) light wavelength 900 nm; F) light wavelength 400 nm.

FIG. 4 illustrates an embodiment of a computer system of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. The illustrative embodiments described in thedetailed description, drawings, and claims are not meant to be limiting.Other embodiments may be utilized, and other changes may be made,without departing from the spirit or scope of the subject matterpresented here. It will be readily understood that the aspects of thepresent disclosure, as generally described herein, and illustrated inthe figures, can be arranged, substituted, combined, and designed in awide variety of different configurations, all of which are explicitlycontemplated and made part of this disclosure.

Light management concepts, which utilize nano- and micron-sizestructuring of interfaces in solar cells, are widely used forperformance improvements. Quantum efficiency (QE) measurements as afunction of light wavelength at a resolution comparable with relevantfeature sizes within a photovoltaic (PV) device provide direct measureof light management effectiveness and electrical properties of the cell,which makes such measurements a useful tool for understanding theinner-workings of solar cells. Certain implementations provide improvedQE measurements of solar cells by providing spatially resolvedinformation of variations in quantum efficiency as a function ofwavelength within the solar cell. In the system described herein,several parameters, such as location, size, wavelength, and intensity ofthe probing beam, can be changed. Combination of precise control overthe spatial position of the beam as well as sensitive electricaldetection currently allows for imaging of solar cell quantum efficiencywith, in one embodiment, a 100-micrometer spatial resolution.

FIG. 1 illustrates an opto-electrical property measurement system of oneembodiment. FIG. 2 provides a schematic illustration of one embodiment,wherein the components represented with dashed borders are optional. Asample to be tested, e.g. a solar cell, is placed on a positioningfixture 112 and in optical communication with a light source 110. Thepositioning fixture 112 provides a “xyz” stage. That is, the positioningfixture 112 is movable in the x-axis, y-axis, and z-axis to provide forprecise spatial positioning of the sample relative to a focal point of abeam of light from the light source 110. An optical fixture 111 isprovided and positioned between the sample 100 and the light source 110.Intensity of a beam illuminating the sample needs to be known foraccurate measurements of opto-mechanical properties; the experimentalimplementation of measurements system may include a beam splitter. Thelight beam from the light source 110 with known intensity illuminatesthe sample 100. This may be accomplished by splitting the beam at theoptical fixture 111 into two beams: a reference beam 201 and a samplingbeam 202. The reference beam 201 is directed to a reference lightdetector 120. The sampling beam 202 is directed to focusing optics 115,which focus the sampling beam 202, for example with a footprint in arange from 1 micrometer to 1 centimeter in the sample plane and focaldepth in a range from 1 micrometer to 1 centimeter perpendicular to thesample plane.

The sampling beam 202 interacts with the testing surface of the sample100 to form an interacted sampling beam 203. A sample light detector 130then detects light that has interacted with the sample such astransmitted light, reflected light or diffused light. In one example ofFIG. 1, the reflected sampling beam 203 is then detected by the samplelight detector 130. The interacted (reflected) sampling beam 203 maypass through one or more of the focusing optics 115 and optical fixture111 prior to being received by the sample detector 130.

Although certain prior art systems probe the sample to determine QE andassume the QE is uniform through the sample, the light beam is probingonly a testing surface on the surface of the sample. The QE data fromthese prior art systems, thus, provides the QE for the testing surface.Variations across the sample are not captured.

The light source 110 may be selected to provide a broad or a narrowspectrum of light. For example, the light source 110 may comprise asingle source of “white” light or may comprise multiple sources of lightof a narrow range of wavelengths. In one implementation, the lightsource has a stable intensity profile as a function of wavelength.

The optical fixture 111 may comprise one or more components for alteringor redirecting the beam of light 200. Components of the optical fixture111 may include, but are not limited to, wavelength selectors, beamsplitters, modulators of light intensity, such as optical choppers, etc.

In one embodiment, a monochromator is utilized to allow selectivecontrol of the wavelength of the beam of light. The monochromator may beprovided as a part of the optical fixture. Controlling the wavelength ofthe light beam allows for a determination of the variations inopto-electrical properties as a function of wavelength. A deviceutilizing a monochromator and the positioning fixture described belowallows for mapping of the entire sample at different wavelengths. In oneembodiment, opto-electrical properties are usually collected within awavelength range of 200 nm to 100,000 nm.

The reference light detector 120 comprises a detector capable ofdetecting and quantifying light. The reference light detector 120determines the intensity of the light illuminating the sample, i.e.provides the reference light quantification. Generally various lightdetectors as known in the art can be utilized. For example, silicondetectors can be used for quantifying light within a wavelength range of400 nm to 1200 nm. Specialty detectors for detection in ultraviolet andinfra-red ranges can be used. In one implementation, it is necessarythat response time for the detector is significantly smaller than thecharacteristic time with which light intensity is modulated. In oneembodiment, the first detector (and the second detector) has a responsetime within the time scale of the sample, for example 10⁻¹⁵ seconds to10⁻⁴ seconds or 10⁻¹² seconds to 10⁻⁶ seconds. The reference lightdetector 120 may be in optical communication with the light source 110directly, as shown by light path 1. As further illustrated in FIG. 2,the reference light detector 120 may, alternatively receive light fromthe illumination source more indirectly, such as: from a split mainlight beam (path 2), after passing through the wave length selector(path 3), or after passing though the modulator (path 4).

The focusing optics 115 are provided, in one implementation, to focusthe beam of light 200, such as the sampling beam 114, on the sample. Thefocusing optics shape the beam of light. The shaping of the beam oflight allows for increased resolution due to control of the area of thesample illuminated. Each lens within the focusing optics will have afocal plane that varies depending on the wavelength of light. Toaccommodate variable wavelengths as described herein, the focusingoptics are adapted to utilize focal tracking.

In one embodiment, the beam of light may be selectively controlled bycontrol of the light source 110, the optical fixture 111, and/or thepositioning fixture. For example, location relative to the sample, size,wavelength, and intensity of the sampling beam 201.

The positioning fixture 112 allows for the controlled placement of thebeam of light 201 on the surface of the sample 100. The positioningfixture 112 is adapted to provide relative movement of the light sourceand the sample. The positioning fixture may be adapted to move thesample or may be adapted to move the light source. In one embodiment,the positioning fixture includes a digital micromirror device. Theability to provide spatially resolved QE maps provides informationregarding the non-uniformity of photovoltaic conversion efficienciesacross a sample. The positioning fixture 112 allows for relativemovement of the beam of light to change what portion of the sample isbeing probed, that is, to move the testing surface. By moving thetesting surface, QE data for a large number of testing surfaces can betaken to provide a QE map of the sample. Thus, it is possible tospatially resolve the sample 100 to provide an image of QE variations ofthe sample. In one implementation, the sample 100 is raster scanned.Systems in accordance with one embodiment provide for resolution of 100μm, preferably resolution of 10 μm. The scan is typically rasteredline-by-line. On each line a predefined number of data points arecollected. Generally speaking, it is more efficient to alternatedirections, that is, if the first line is rastered from left to right,the second is rastered from right to left. Resolution of the scan isdetermined by at least two factors: the accuracy of sample positioning,point-to-point distance, and the size of the beam. In the schemepresented in FIG. 3 resolution is limited by the size of the beam andstep-size, which are on the order of 100 micrometers, while accuracy inpositioning is on the order of 100 nm. The maximum resolution for thistechnique is about 1 micrometer due to the diffraction limit

In an embodiment, the positioning fixture is controllable and incommunication with a focal point tracker to position the testing surfacein the focal plane. That is, in one embodiment, the sample may be movedin the “Z” plane. In most optical systems, position of the focal planechanges as a function of wavelength. Thus, tracking focal plane iscrucial for obtaining data about light-induced phenomena with highspatial resolution. In particular, the use of a monochromator toselectively provide a wavelength of light and the variation in QE basedupon wavelength can be utilized to more completely map the sample whenthe sample can be adjusted to the focal plane of the selectedwavelength. The position of the focal plane at each wavelength isdetermined prior to QE measurements and a correcting signal is sent fromthe controller to compensate for shift in the focal plane.

At least one sample light detector 130 may be used for detecting lightthat has interacting with the sample, such as reflection, diffusion, ortransmission. As seen in FIG. 2, the sample light detector 130 may be areflectance light detector positioned in optical communication with thesample and the focusing optics 115. Silicon detectors can be used forquantifying light within a wavelength range of 400 nm to 1200 nm.Specialty detectors for detection in ultraviolet and infra-red rangescan also be used. It is necessary that response time for the detector issignificantly smaller than the characteristic time with which lightintensity is modulated.

In one embodiment, an electrical signal device 140 for the measurementof electrical properties of the sample is utilized. The electric signaldevice 140 is in communication with the sample. In one embodiment, theelectric signal device 140 converts the electrical signal from thesample into analog voltage that can be interpreted by a data collectiondevice. In one embodiment, the electric circuit 140 may include, but isnot limited to one or more oscilloscopes, current amplifiers, voltageamplifiers, semiconductor parameter analyzers.

In one implementation, one or more bias is applied to the sample. Asillustrated in FIG. 2, a light bias 160 and/or an electrical bias 161may be applied to the sample. The applied bias further provides dataregarding the bias to the data collection device as illustrated in FIG.2.

A data collection device 170 may be utilized to collect, route, store,or pre-process information from one or more of the reference detector120, sample detector 130, optical fixture 111, positioning fixture 112,the bias 160, 161, and the electric signal device 140. The datacollection device 170 may be in communication with a controller orprocessor 180. The data collection device 170 may record the informationit receives for storage or it may be stored in temporary memory. Theinformation collected from the components of the system may furtherinclude a “time-stamp”. It will be appreciated that the time stamp maybe utilized to correlate the information from various components for anindication of behavior at a given time.

In one implementation a processor 180 is utilized. The processor may bein communication with one or more components of the system, includingthe light source 110, the reference light detector 120, the sample lightdetector 130. In further implementations, the processor may also be incommunication with the positioning fixture 112 to control the spatialposition of the sample such that the processes can send signals tocontrol the components. Further, the processor 180 may receiveinformation from the data collection device 170 or directly from one ormore of the reference detector 120, sample detector 130, optical fixture111, positioning fixture 112, the bias 160, 161, and the electric signaldevice 140, for example for “on-board” analog processing in certainembodiments.

In certain implementations, correlated digital analysis of the signalsfrom light detectors 120, 130 and the sample may be done. Theinformation from the components of the system may undergo analysis fortime-resolved correlations between the electrical response (electricsignal device) and optical excitation (light detector). Digital dataanalysis of the data acquired with high temporal resolution allows forfast and accurate measurements of light-induced phenomena in the sample.Examples of digital data analysis include but are not limited to:Hadamard transform, plain averaging of the step-functions, temporalaveraging of electrical and/or light characteristic signals and temporaland spatial correlation analysis of electrical and/or lightcharacteristic signals, averaging of electrical response during low andhigh light intensity; the absolute difference between two electricalresponses normalized by the absolute difference in energy of incidentlight is proportional to quantum efficiency of the sample; infinitelyfast increase in intensity of light results in delayed increase inelectrical current where rise time and fall time are correlated with themobility of minor carriers within the solar cell (when the sample issolar cell); and correlation of electrical signal with the change inintensity using sine function instead of step function provideadditional information about charge dynamics within the sample inducedby light beam.

One or more implementations utilize opto-electrical properties,including but not limited to QE by analyzing step function profile,carrier dynamics by analyzing delay in current response with respect toillumination response. In one implementation, the analyses are done fortime-resolved data collected at a single spatial location on the sample.

In certain embodiments, the opto-electrical properties measured by thesystem include QE. The QE maybe calculated from the data from thedetectors 120, 130 using conventional external QE and internal QEcalculations.

Further, in one implementation the detector determines the time-resolvedQE. That is, one can measure QE data for a testing surface during thetime it takes for the sample to reach a saturation current following theonset of illumination or the time-dependent behavior following theremoval of the illumination. The QE profile reflects physical phenomenaoperating within the device.

One implementation of a system for QE measurement is capable ofproviding spatially resolved data about solar cell degradation.Spatially resolved information about solar cell quantum efficiencyprovides experimental data, which enables development of accuratephysical models of solar cell degradation.

Certain implementations of the systems and methods described herein maybe used with photovoltaics. Further, QE tools are invaluable in avariety of other applications such as optical characterization, processcontrol, quality control, and basic R&D. Specific embodiments include:(i) industrial quality assurance during production of light-sensitivesemiconducting devices, such as solar cells, photodetectors, CCD, lightsensors, etc., identification of production defects based onspatially-resolved light-wavelength dependent measurements of quantumefficiency; (ii) early-stage failure prediction (defectcharacterization) in light-sensitive semiconductor devices, smallchanges in optical/electrical properties of semiconductors precedingcatastrophic failure can be evaluated using spatially-resolvedlight-wavelength dependent measurements of quantum efficiency; (iii)throughput of the measurements can be improved using digital micromirrordevice technology, illumination of the solar cell is performed using asingle-color pixel moving across the screen while electrical currentgenerated by the solar cell is detected. The size of the pixel iscontrolled by the distance between a micro-mirror chip and the sample aswell as by the focal point tracking technology; and (iv) solar cell andphotodetector research.

In one embodiment, shown in FIG. 4, a system 1000 is provided forspatially resolved imaging as described. FIG. 4 shows an exemplary blockdiagram of an exemplary embodiment of a system 1000 according to thepresent disclosure. For example, an exemplary procedure in accordancewith the present disclosure can be performed by a processing arrangement1100 and/or a computing arrangement 1100. Such processing/computingarrangement 1100 can be, e.g., entirely or a part of, or include, butnot limited to, a computer/processor that can include, e.g., one or moremicroprocessors, and use instructions stored on a computer-accessiblemedium (e.g., RAM, ROM, hard drive, or other storage device).

As shown in FIG. 4, e.g., a computer-accessible medium 1200 (e.g., asdescribed herein, a storage device such as a hard disk, floppy disk,memory stick, CD-ROM, RAM, ROM, etc., or a collection thereof) can beprovided (e.g., in communication with the processing arrangement 1100).The computer-accessible medium 1200 may be a non-transitorycomputer-accessible medium. The computer-accessible medium 1200 cancontain executable instructions 1300 thereon. In addition oralternatively, a storage arrangement 1400 can be provided separatelyfrom the computer-accessible medium 1200, which can provide theinstructions to the processing arrangement 1100 so as to configure theprocessing arrangement to execute certain exemplary procedures,processes and methods, as described herein, for example.

System 1000 may also include a display or output device, an input devicesuch as a key-board, mouse, touch screen or other input device, and maybe connected to additional systems via a logical network. Many of theembodiments described herein may be practiced in a networked environmentusing logical connections to one or more remote computers havingprocessors. Logical connections may include a local area network (LAN)and a wide area network (WAN) that are presented here by way of exampleand not limitation. Such networking environments are commonplace inoffice-wide or enterprise-wide computer networks, intranets and theInternet and may use a wide variety of different communicationprotocols. Those skilled in the art can appreciate that such networkcomputing environments can typically encompass many types of computersystem configurations, including personal computers, hand-held devices,multi-processor systems, microprocessor-based or programmable consumerelectronics, network PCs, minicomputers, mainframe computers, and thelike. Embodiments of the invention may also be practiced in distributedcomputing environments where tasks are performed by local and remoteprocessing devices that are linked (either by hardwired links, wirelesslinks, or by a combination of hardwired or wireless links) through acommunications network. In a distributed computing environment, programmodules may be located in both local and remote memory storage devices.

Example

Performance of an embodiment of a QE system was demonstrated by imagingthe back-side current collectors of a silicon solar cell throughvariations in quantum efficiency as well as imaging composition-inducedspatial variations of quantum efficiency with approximately100-micrometer resolution. The system used in the experiment is amodified Newport EQE-200 with home built data acquisition and samplepositioning software. The optical part of the system contains a 250 Wquartz tungsten halogen lamp (Newport 66884), optical chopper (Newport75158), monochromator (Newport, ⅛ m Cornerstone 74004), siliconphotodetector (Thorlabs PDA 36A), and current amplifier (FemtoDLPCA-200). The sample positioning and control system contains atranslation stage (Thorlabs MTS25C-Z8), a digital data acquisition card(NI-PCI-6115 DAQ) and a LabView/MATLAB control software for samplepositioning and data acquisition. FIG. 3A shows QE maps with better than50-micrometer point-to-point resolution. The wavelength dependence of QEmaps (FIGS. 3B-3D) provides information about different interfaces inthe solar cell. At long wavelengths, absorber bandgap largely determinesQE. Thus, the QE map in the near-IR region (FIG. 3B) providesinformation about variations of the absorber bandgap. The structure ofthe anti-reflective coating of the PV cells was revealed from the QEmaps in the UV-region (FIG. 3D).

FIGS. 3A-D illustrate spatially resolved QE maps (oversaturated linesare the top current collectors in A-D): A) light wavelength 1100 nm(spatial variations of QE ˜50-100 μm are visible); B) light wavelength1100 nm (current collector square grid is visible); C) light wavelength1000 nm; D) light wavelength 800 nm (spatial variations of QE ˜50-100 μmare visible); FIGS. 3E and F illustrate a spatially resolved QE map froma prior commercial machine: E) light wavelength 900 nm; F) lightwavelength 400 nm. A comparison of the QE maps of FIG. A-D compared toE-F shows that features in the ˜50 μm range are visible with a system ofthe present invention.

The results using a prior system are illustrated in FIGS. 3E and 3F.FIGS. 3E and 3F illustrate that the prior art system produces QE mapwhere even features in the 500 μm range are difficult to resolve.

Various embodiments are described in the general context of methodsteps, which may be implemented in one embodiment by a program productincluding computer-executable instructions, such as program code,executed by computers in networked environments. Generally, programmodules include routines, programs, objects, components, datastructures, etc. that perform particular tasks or implement particularabstract data types. Computer-executable instructions, associated datastructures, and program modules represent examples of program code forexecuting steps of the methods disclosed herein. The particular sequenceof such executable instructions or associated data structures representsexamples of corresponding acts for implementing the functions describedin such steps.

Software and web implementations of the present invention could beaccomplished with standard programming techniques with rule based logicand other logic to accomplish the various database searching steps,correlation steps, comparison steps and decision steps. It should alsobe noted that the words “component” and “module,” as used herein and inthe claims, are intended to encompass implementations using one or morelines of software code, and/or hardware implementations, and/orequipment for receiving manual inputs.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations may be expressly set forth herein for thesake of clarity.

The foregoing description of illustrative embodiments has been presentedfor purposes of illustration and of description. It is not intended tobe exhaustive or limiting with respect to the precise form disclosed,and modifications and variations are possible in light of the aboveteachings or may be acquired from practice of the disclosed embodiments.It is intended that the scope of the invention be defined by the claimsappended hereto and their equivalents.

What is claimed is:
 1. A system for measuring the opto-electricalproperties of a sample, comprising: a light source; a reference lightdetector in direct communication with the light source measuring lightintensity output of the light source as a function of light wavelength;an optical fixture in optical communication with the light source; apositioning fixture configured to provide three-dimensional positioningof the sample relative to the light source; a sample light detector inoptical communication with the sample to receive light from the sample;a focal plane tracker adapted to determine the focal plane of thefocusing optics and adjust the three-dimensional positioning of thesample relative to the light source; and an electric signal device forthe measurement of electrical properties of the sample.
 2. The system ofclaim 1, wherein the light detectors have a response time of betweenabout 10⁻¹⁵ seconds to 10⁻⁴ seconds.
 3. The system of claim 1, whereinthe sample light detector is selected from the group consisting of atransmission detector, a reflection detector, and a diffusion detector.4. The system of claim 1, further comprising focusing optics positionedin optical communication with the light source and the sample.
 5. Thesystem of claim 4, further comprising a bias in communication with thesample.
 6. The system of claim 5, further comprising a data collectiondevice in communication with one or more of the reference detector,sample detector, optical fixture, positioning fixture, the bias, and theelectric signal device.
 7. The system of claim 6, further comprising afocal plane tracker adapted to determine the focal plane of the focusingoptics and adjust the three-dimensional positioning of the samplerelative to the light source.
 8. Method for data acquisition ofspatially resolved opto-electrical signal from a sample comprising:positioning the sample relative to a light source to define a firstportion of the sample; emitting a first light beam from the lightsource; measuring intensity of the light output of the light sourcewithin a specified bandwidth; interacting the first sampling beam withthe first portion of the sample; detecting interacted light with asample light detector; repositioning the sample relative to a lightsource to define a second portion of the sample; emitting a second lightbeam from the light source; measuring intensity of the light output ofthe light source within the specified bandwidth; interacting the secondsampling beam with the second portion of the sample; detecting thereflected second sampling beam with a second light detector; collecting,via a data collection device, time-stamped intensity of the light outputof the light source for the first light beam within specified bandwidth;collecting, via a data collection device, time-stamped first light beamelectrical response of the sample; and collecting, via a data collectiondevice, time-stamped first light beam interacted light intensity.
 9. Themethod of claim 8 further comprising collecting, via a data collectiondevice, time-stamped intensity of the light output of the light sourcefor the second light beam within specified bandwidth; collecting, via adata collection device, time-stamped second light beam electricalresponse of the sample; and collecting, via a data collection device,time-stamped second light beam interacted light intensity.
 10. Themethod of claim 8, further comprising applying, by a computer, amathematical algorithm for correlation of time-stamped electricalresponse from the sample with the corresponding time-stamped intensityand time stamped interacted light intensity.
 11. The method of claim 8,wherein positioning the sample relative to a light source to define afirst portion of the sample comprises positioning the first light beamwith a positioning fixture.
 12. The method of claim 8, whereinpositioning the sample relative to a light source to define a firstportion of the sample comprises positioning the sample with apositioning fixture.
 13. The method of claim 12, further comprisingdetermining the focal plane of a focusing optic and adjusting theposition of the sample with the positioning fixture to place the samplein the focal plane.
 14. A computer-implemented machine for collectingspatially resolved signals of opto-electrical properties of a samplecomprising: a processor; and a tangible non-transitory computer-readablemedium operatively connected to the processor and including computercode configured to: position the sample with a positioning fixture todefine a first portion of the sample; 1) emit a light beam from a lightsource; 2) measure intensity of the light output of the light sourcewithin specified bandwidth; 3) detect the reference beam with areference detector; 4) reflect the sampling beam on the first portion ofthe sample; 5) detect the reflected sampling beam with a sampledetector; 6) collect time-stamped intensity of the light output of thelight source within specified bandwidth; 7) collect time-stampedelectrical response of the sample; 8) collect time-stamped intensity ofthe reflected sampling beam; 9) record position of the sample; andreposition the relative position of either the sample or light source tothe other to define another portion of the sample for whichopto-electrical properties have not been calculated and repeat steps1-9.
 15. The computer implemented machine of claim 14, wherein theprocessor is further configured to apply a mathematical algorithm forcorrelation of time-stamped electrical response from the sample with thecorresponding time-stamped intensity and time stamped interacted lightintensity.
 16. The computer implemented machine of claim 14, wherein theprocessor is further configured to position the sample relative to alight source to define a first portion of the sample comprisespositioning the first light beam with a positioning fixture.
 17. Thecomputer implemented machine of claim 14, wherein the positioningfixture comprises a digital micromirror device.
 18. The computerimplemented machine of claim 14, wherein the processor is furtherconfigured to position the sample relative to a light source to define afirst portion of the sample comprises positioning the sample with apositioning fixture.
 19. The computer implemented machine of claim 14further comprising a focusing optic positioned in optical communicationwith the light source and the sample.
 20. The computer implementedmachine of claim 19, wherein the processor is further configured todetermine the focal plane of the focusing optic and adjusting theposition of the sample with the positioning fixture to place the samplein the focal plane.